Korvac had absorbed some of Galactus's powers, and if I remember correctly, he was able to resurrect Starhawk after he killed and or defeated him, and at the end he resurrected the Avengers that he killed. Have we ever seen Galactus do This? I heard/read that he was shown to resurrect someone connected to Beta Ray Bill that died. Does anyone know when this Happened? Is this a regular for him, or was this just a one-time Thing? Thanks.

He has specifically said no before but it is unclear what he meant. As he brought Morg and others back. He has brought near dead beings back fairly recently in Stormbreaker and Silver Surfer during the Annihilation aftermath (Surfer nearly being killed by two Galactus level beings).

Korvac absorbed the energy/knowledge from TaaII. Not really Galactus himself. Although, the entire energy of the ship is pretty vast. Galactus absorbed it, or was trying to, before his battle with the Beyonder in the SWs.

When Doom jumped in and took the power he was able to warp reality etc.